Heavy duty electrical connector and strain relief therefor

ABSTRACT

An integral strain relief for a heavy duty electrical connector that includes a housing made of two telescoped, cupshaped nylon sections each of which has an eccentric opening in a transverse wall. The openings are of approximately equal diameters and of the same eccentricity so that when the sections are mutually related the two openings move between alignment and partial disalignment. The two openings are sized to pass a heavy duty insulated electric cable for connection to electric terminals inside the housing when the openings are substantially aligned. Upon subsequent relative rotation of the two housing sections and partially disalignment of the two openings, said openings crimp and thereby clamp the cable thus applying a holding force that relieves the strain that would otherwise be induced at the terminals when an external pulling force is applied to the cable.

United States Patent [191 Ludwig 1 Feb. 11, 1975 HEAVY DUTY ELECTRICALCONNECTOR AND STRAIN RELIEF THEREFOR [75] Inventor: Melvin Ludwig, GreatNeck, NY.

[73] Assignee: Eagle Electric Mgf. Co. Inc., Long Island City, NY.

[22] Filed: Oct. 10, 1973 [21] Appl. No.: 405,027

[52} U.S. Cl. 339/103 R, 24/132 AB, 174/135 [51] Int. Cl l-I0lr 13/58[58] Field of Search 339/103-107, 339/187, 274; 174/135; 24/115 G, 132AA,

132 AB, 132 AC, 249 SA [56] References Cited 1,151,845 7/1963 Germany174/135 Primary Examiner-Roy D. Frazier Assistant Examiner-Lawrence J.Staab Attorney, Agent, or Firm--Kirschstein, Kirschstein,

Ottinger & Frank [57] ABSTRACT An integral strain relief for a heavyduty electrical connector that includes a housing made of twotelescoped, cupshaped nylon sections each of which has an eccentricopening in a transverse wall. The openings are of approximately equaldiameters and of the same eccentricity so that when the sections aremutually related the two openings move between alignment and partialdisalignment. The two openings are sized to pass a heavy duty insulatedelectric cable for connection to electric terminals inside the housingwhen the openings are substantially aligned. Upon subsequent relativerotation of the two housing sections and partially disalignment of thetwo openings, said openings crimp and thereby clamp the cable thusapplying a holding force that relieves the strain that would otherwisebe induced at the terminals when an external pulling force is applied tothe cable.

9 Claims, 7 Drawing Figures HEAVY DUTY ELECTRICAL CONNECTOR AND STRAINRELIEF THEREFOR BACKGROUND OF THE INVENTION 1. Field of the Invention Animproved strain relief for heavy duty electrical connectors.

2. Description of the Prior Art Strain relief means for electricalconnectors are quite common. However, as to heavy duty electricalconnectors, the strain relief products presently available on the marketsuffer from several defects. They are quite costly to manufacture andare complex in construction. For the most part, the prior art structuresdo not provide sufficiently good strain relief. In addition; the priorart devices are frequently difficult .to manipulate and are ungainly.

In one form of prior art connector a metal cap mounted on the connectorhousing has a pair of arcuate rearwardly projecting segments. Thesegments face one another and are movable towards and away from thelongitudinal axis of the connector. Adjustable fastener means is used tosecure ears on the segments to one another in a manner that permits thespace between the segments to be varied. An electrical cable is threadedbetween the segments when they are spaced widely apart; the cable isconnected to terminals within the connector; then the fastener means istightened in order to shift the arcuate segments towards one anotheruntil they clamp the cable between them. The two confronting segmentsact as a strain relief.

In another example of the prior art a first arcuate segment is formedintegrally with one of the housing sections while a second arcuatesegment, that faces the first segment, is movable with respect thereto.Once again adjustable fastener means is used to couple the segments. Thecable is connected to terminals within the connector and then thefastener means is manipulated to shift the movable segment into aclamping position against the cable.

Still another example of the prior art is a .Iacobs chuck type of strainrelief means. The connector housing is made in two parts, one of whichlongitudinally shifts upon relative rotation of the parts. A set ofthree flexible jaws on one part extends through a central opening in theother part. The cable is threaded between the opening defined by thetips of the jaws. When the parts are relatively rotated, the tips of thejaws approach one another to clamp the cable.

SUMMARY OF THE INVENTION Brief Description of the Invention The presentinvention provides a connector that is adapted to be located at one endof an insulated, electrically conductive wire, i.e., cable. Theconnector has a plastic, preferably nylon, housing comprised of twogenerally cup-shaped sections each of which is probetween opposed sidesthereof when the sections are mutually rotated to sufficiently disalignthe openings.

Means is provided for limiting the relative rotational displacement ofthe housing sections in an openingdisaligning (clamping) direction.Means also is provided to limit the relative rotation to such directionso that the sections after clamping the cable will retain their grip andnot back off. Cancelling means further is included for disabling theuni-directional/rotation limiting means when the cable is to bedisconnected.

Purpose of the Invention It is an object of this invention to provide animproved strain relief means for a heavy duty electrical connector.

Another object of the present invention is to provide an improved heavyduty electrical connector having 1 strain relief means integraltherewith.

Another object of the present invention is to provide an improved heavyduty electrical connector having means for retaining an integral strainrelief means in a cable clamping position.

Another object of the present invention is to provide an improved heavyduty electrical connector having strain relief means, as describedabove, that includes means for disabling the retaining means.

Another object of the present invention is to provide means in a heavyduty electrical connector, as described above, that normally preventsthe housing sections thereof from moving away from a cable receivingcondition.

Another object of the present invention is to provide an improved heavyduty electrical connector, as described above, that includesinterlocking means for preventing inadvertent separation of the twosections of the connector housing.

Other objects of the invention will in part be obvious and in part willbe pointed out hereinafter.

The invention accordingly consists in the-features of construction,combinations of elements, and arrangement of parts which will beexemplified in the construction hereinafter described, and of which thescope of application will be indicated in the appended claims.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an exploded perspective view,partially broken away and partially in section, illustrating oneembodiment of the present invention;

FIG. 2 is a top view of the device shown in FIG. 1, the relativepositions of the housing sections being that of a cable-passing mode;

FIG. 3 is a side view, partially broken away and partially in section,illustrating constructional features of the present invention;

FIG. 4 is a transverse sectional view, taken substantially along theline 4-4 of FIG. 3;

FIG. 5 is another transverse sectional view, similar to FIG. 4, butillustrating the relative positions of the housing sections at the timeof their assembly;

FIG. 6 is another transverse sectional view, similar to FIG. 4, butillustrating the relative positions of the housing sections in acable-clamping mode; and

FIG. 7 is a fragmentary sectional view showing a particular feature ofthe present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,and in particular to FIGS. 1-3, it will be seen that the heavy dutyconnector comprising the present invention includes a cupshaped bodysection 12, a cup-shaped cap section 14 that is concentricallytelescoped over the closed end of the body section 12 and an end plug 16that is received in and secured to the open end of the body section 12.All of the three foregoing components preferably are molded of asynthetic plastic material, such as nylon or a phenolformaldehydecondensation product, in order to provide the connector 10 with theappropriate electrical insulation and heat resistant characteristics.Selected areas of the outer surface of the body section 12 and of thecap section 14 may be finished with knurling or the like to facilitateusage of the connector 10 in a manner such as will be described indetail hereinafter, i.e., relative rotation by hand.

The body section 12 is defined by a generally cylindrical sleeve 20having an integral transverse wall 22 formed across one end thereof. Theopposite end of the sleeve 20 is open and includes a downwardlyextending annular lip 24 defining an annular seat 26, and integrallyformed bosses or lugs 28 that are provided with longitudinallyextending, internally threaded bores 30.

An longitudinally extending through opening 32 is formed in the end wall22 of the body section 12, being positioned eccentrically with respectto the longitudinal axis of said body section. Preferably, although notnecessarily, at least a portion of the lower corner of the opening 32 isprovided with a chamfer, i.e. bevel, 32a.

for a purpose described hereinafter.

As shown for example in FIGS. 1 and 4-6, an integral concentricincomplete gear segment 34 is formed on the periphery of the end wall22. A single tooth 36, at one end of the segment 34 is made larger thanthe other teeth. In addition, in a position longitudinally below theplane of the teeth of the rack 34, the end wall 22 is provided with apair of longitudinally extending widely angularly spaced notches orgrooves 38 (only one of which is shown) in FIG. 1 that are positionedother than 180 degrees apart. The notches 38 are located in a fulldiametric portion 40 that is spaced longitudinally above the remainderof the cylindrical section 20 in order to define an annular recess orundercut 42.

Turning now to the cap section 14 it will be seen, particularly in FIG.1, that it has an end wall 50 in which a longitudinally extendingopening 52 is formed. The opening 52 is of the same diameter as theopening 32 and has the same radius of eccentricity. The openings arelarge enough to pass a heavy duty insulated electrical cable.Preferably, although not necessarily, the opening 52 is chamfered as at52a. As will be explained more fully hereinafter, the openings 32 and52, as well as the chamfers 32a and 52a, cooperate with one another toclamp the insulation portion of the wire that passes therethrough. Theend wall 50 is, in addition, provided with a through slot 54 that ispositioned adjacent a lug 56 (see FIG. 5) formed on the inside surfaceof the cap 14. A resilient leaf pawl 58 has an edge suitably retained ina slot 59 formed in the lug 56 and passes across and directly beneaththe slot 54. The cap 14 includes with a pair of opposed integralprojections 60 that extend radially inwardly from the inside surfacethereof. The projections 60 are angularly spaced apart by an are equalto that separating the notches 38. To facilitate molding of the cap 14,a pair of mold-pinpassing openings 62 in the wall 50 are aligned withthe projections 60. i I

The end plug 16 is molded with an integral flange 64 that mates with theannular lip 24 and a reduced diameter portion 66 that mates with theannular seat 26 in the body section 12. A pair of clearance throughholes 68 are formed in the end plug 16 in order to permit fasteners,such as screws 70, to pass therethrough and threadingly engage thetapped bores 30 in the body section 12. In the particular embodimentillustrated, a pair of male contact prongs 72, the offset shanks of eachof which includes a tapped opening in which a screw 74 is received, aremounted in theend plug 16. After the insulated electrical cable ispassed through the openings 32 and 52 the electrically conductive coresthereof, which may be either solid or stranded, are secured to thecontacts 72 as by the screws 74. It should be understood that while malecontacts have been illustrated, the scope of the present invention alsoincludes the use of female contacts.

The connector 10 of the present invention is supplied to the consumerwith the telescoped section in the relative angular relationshipillustrated in FIG. 5. The cap section 14 has been telescoped over thebody section 12. To accomplish this the lugs 60 have been passedlongitudinally through the slots 38 and the pawl 58 has been positionedto the side of the enlarged tooth 36. The openings 32 and 52 were almostin registery with one another remote from the remaining teeth (see FIG.4). The cap section 14 and the body section 12 then were rotatedrelative to one another so that pawl 58 was forced over the enlargedtooth 36. The lugs 60 thereby were positioned in the annular recess 42away from the notches 38. It will be appreciated that the cap section 14cannot be removed from thebody section 12 without forcing the pawl 58back over the enlarged tooth 36 and this is extremely difficult sincethe tooth 36 is provided with a buttress back face that is at an anglethat resists reverse rotation, being almost perpendicular to the lengthof the pawl. The openings 32 and 52 are now in registry. The remainingteeth of the gear segment are also of. buttress shape to inhibit, inconjunction with the pawl 58, reverse rotation. The connector 10 is nowready for the insertion of an electric cable through the openings 32 and52.

After the conductor ends are connected to the contacts, further relativerotation of the cap section 14 and the body section 12 to the positionshown in FIG. 6, causes the pawl 58 to ride successively over the teeth34 until a desired clamping position is reached. At this time, andbecause of the relative rotation; the regis tered portions ofthe twoopenings 32 and 52 will be reduced in size and will assume a generalshape of an oval having sharg ends (see FIG. 6). The curved edges of theoval shaped opening engage and tightly squeeze the insulation of thecable. The chamfered edges 32a and 52a are preferable in that only smallareas engage the insulation and thereby increase the available pressureon the wire as a function of the twisting forces exerted by the user.

It will be appreciated from the above that the pawl and ratchetarrangement afforded by the pawl 58 and the buttress teeth 34effectively provide means for limiting the cap 14 to rotation in asingle direction that tends to clamp the insulated cable. When it isdesired to remove the insulated cable, a tool, such as a screw driver,nail, nail tile or the like, is inserted through the opening 54 in thecap 14 and manipulated to shift the pawl 58 away from the teeth 36. Withthe pawl 58 disengaged from the teeth 34, the cap section 14 and thebody section 12 may be counterrotated easily to release the wire fromthe confronting openings 32 and 52.

It will be evident from the foregoing that an improved strain reliefmeans has been provided for a heavy duty electrical connector. Thestrain relief means is integral with the electrical connnectorcomprising this invention and may be locked in place in a wire clampingmode by the pawl and ratchet arrangement. Means also is provided fordisabling the locking means and returning the connector parts to aninitial position that readily permits removal of the cable andsubsequent reinsertion of the same on a different cable. Theconstruction of the present invention provides interlocking means thatprevents the inadvertent separation of the two housing sections, whichnormally limits the relative movement of the housing sections to adirection towards a clamping position and which also prevents the twohousing sections from moving away from the clamping position to the wirereceiving condition.

It thus will be seen that there is provided a device which achieves theseveral objects of the invention and which is well adapted to conditionsof practical use.

As various possible embodiments might be made of the above invention,and as various changes might be made in the embodiment above set forth,it is to be understood that all matter herein described, or shown in theaccompanying drawings, is to be interpreted as illustrative and not in alimiting sense.

Having now described the invention, there is claimed as new and desiredto be secured by Letters Patent:

1. A heavy duty electrical connector adapted to be secured to an end ofan insulated electrical cable having conductive cores, said connectorcomprising:

a. a body section including a transverse wall having an eccentricallydisposed through opening for passing the cable therethrough;

b. a cap section telescopically associated with said body section, saidcap section including a transverse wall having an eccentrically disposedthrough opening for passing the cable therethrough, said openings beingof the same diameter and of the same radius of eccentricity, saidopenings in said cap section initially being in substantial alignmentwith said opening in said body section, said cap section being angularlyrotatable relative to said body section in a first direction toprogressively shift said openings out of alignment thereby to distortand clamp the insulation of the cable between opposed edges of saidopenings;

c. means limiting the angular rotation of said cap section to said firstdirection so as to lock said cap in cable clamping position, saidlimiting and locking means comprising a ratchet and a cooperating pawl,

d. contacts carried by said body section, said contacts including meansfor electrically and mechanically coupling the conductive cores of thecable thereto; and

e. manually operable means for selectively disabling the limiting andlocking means.

2. The connector in accordance with claim 1 wherein said ratchet isintegral with said body section and said pawl is integral with said capsection.

3. The connector in accordance with claim 1 wherein said cap sectionincludes a slot through said transverse wall thereof for receiving atool that is adapted to disengage said pawl from said ratchet to therebyto disable the limiting and locking means.

4. The connector in accordance with claim l wherein the first tooth ofsaid ratchet normally prevents said openings from moving out of initialalignment with each other absent an angular force on said cap that movessaid pawl past said first tooth.

5. The connector in accordance with claim 3 wherein said first tooth ofsaid ratchet is enlarged with respect to the remainder of the teeththereof.

6. The connector in accordance with claim 1 wherein at least a portionof the peripheral edge of said opening in said cap section, and at leasta portion of the peripheral edge of said opening in said body sectionare chamfered.

7. The connector in accordance with claim 1 wherein there is furtherincluded interlocking means on said cap section and said body sectionfor preventing inadvertent separation thereof.

8. The connector in accordance with claim 7 wherein said interlockingmeans comprises a pair of radially inwardly extending projectionsintegral with said cap section and an annular groove on the peripheralsurface of said body section said projections being spaced apart by anangle other than degrees said body section including a pair ofperipheral notches that are angularly spaced apart the same as theprojections, said notches extending from an end of the body section tothe groove whereby said projections are longitudinally movable throughsaid notches to the groove and then angularly movable in said groove.

9. A heavy duty electrical connector adapted to be secured to an end ofan insulated electrical cable having conductive cores, said connectorcomprising:

a. a body section including a transverse wall having an eccentricallydisposed through opening for passing the cable therethrough;

b. a cap section telescopically associated with said body section, saidcap section including a transverse wall having an eccentrically disposedthrough opening for passing the cable therethrough, said openings beingof the same radius of eccentricity,

said opening in said cap section initially being in substantialalignment with said opening in said body section, said cap section beingangularly rotatable relative to said body section in a first directionto progressively shift said openings out of alignment thereby to distortand clamp the insulation of the cable between opposed edges of saidopenings;

c. means limiting the angular rotation of said cap section to said firstdirection so as to lock said cap in cable clamping position, saidlimiting and locking means comprising a ratchet and a cooperating pawl,

(1. contacts carried by said body section, said contacts including meansfor electrically and mechanically coupling the conductive cores of thecable thereto; and

e. manually operable means for selectively disabling the limiting andlocking means.

1. A heavy duty electrical connector adapted to be secured to an end ofan insulated electrical cable having conductive cores, said connectorcomprising: a. a body section including a transverse wall having aneccentrically disposed through opening for passing the cabletherethrough; b. a cap section telescopically associated with said bodysection, said cap section including a transverse wall having aneccentrically disposed through opening for passing the cabletherethrough, said openings being of the same diameter and of the sameradius of eccentricity, said openings in said cap section initiallybeing in substantial alignment with said opening in said body section,said cap section being angularly rotatable relative to said body sectionin a first direction to progressively shift said openings out ofalignment thereby to distort and clamp the insulation of the cablebetween opposed edges of said openings; c. means limiting the angularrotation of said cap section to said first direction so as to lock saidcap in cable clamping position, said limiting and locking meanscomprising a ratchet and a cooperating pawl, d. contacts carried by saidbody section, said contacts including means for electrically andmechanically coupling the conductive cores of the cable thereto; and e.manually operable means for selectively disabling the limiting andlocking means.
 2. The connector in accordance with claim 1 wherein saidratchet is integral with said body section and said pawl is integralwith said cap section.
 3. The connector in accordance with claim 1wherein said cap section includes a slot through said transverse wallthereof for receiving a tool that is adapted to disengage said pawl fromsaid ratchet to thereby to disable the limiting and locking means. 4.The connector in accordance with claim 1 wherein the first tooth of saidratchet normally prevents said openings from moving out of initialalignment with each other absent an angular force on said cap that movessaid pawl past said first tooth.
 5. The connector in accordance withclaim 3 wherein said first tooth of said ratchet is enlarged withrespect to the remainder of the teeth thereof.
 6. The connector inaccordance with claim 1 wherein at least a portion of the peripheraledge of said opening in said cap section, and at least a portion of theperipheral edge of said opening in said body section are chamfered. 7.The connector in accordance with claim 1 wherein there is furtherincluded interlocking means on said cap section and said body sectionfor preventing inadvertent separation thereof.
 8. The connector inaccordance with claim 7 wherein said interlocking means comprises a pairof radially inwardly extending projections integral with said capsection and an annular groove on the peripheral surface of said bodysection said projections being spaced apart by an angle other than 180degrees said body section including a pair of peripheral notches thatare angularly spaced apart the same as the projections, said notchesextending from an end of the body section to the groove whereby saidprojections are longitudinaLly movable through said notches to thegroove and then angularly movable in said groove.
 9. A heavy dutyelectrical connector adapted to be secured to an end of an insulatedelectrical cable having conductive cores, said connector comprising: a.a body section including a transverse wall having an eccentricallydisposed through opening for passing the cable therethrough; b. a capsection telescopically associated with said body section, said capsection including a transverse wall having an eccentrically disposedthrough opening for passing the cable therethrough, said openings beingof the same radius of eccentricity, said opening in said cap sectioninitially being in substantial alignment with said opening in said bodysection, said cap section being angularly rotatable relative to saidbody section in a first direction to progressively shift said openingsout of alignment thereby to distort and clamp the insulation of thecable between opposed edges of said openings; c. means limiting theangular rotation of said cap section to said first direction so as tolock said cap in cable clamping position, said limiting and lockingmeans comprising a ratchet and a cooperating pawl, d. contacts carriedby said body section, said contacts including means for electrically andmechanically coupling the conductive cores of the cable thereto; and e.manually operable means for selectively disabling the limiting andlocking means.